i mean there's still so much to wrap up. they have so many plots going on i feel as though they may rush the conclusion making it feel unsatisfying. here's to name a few plot points they need to wrap up:
the reach's invasion on earth
the justice league's trial
the runaways and what their role is
aqualad and his recovery (although midway through that)
chesire and sportsmaster's revenge
the light's plan.
i feel as though there are only so many episodes that there will not be a satisfying conclusion and that they may have planned to answer in a third that will never happen.